From Science & Research The demonstration of these favourable properties and biobased origins still lacks an explanation for circularity. A solution for a polymer’s end-of-life that enables the recycled material to re-enter the values stream is the holy grail of a circular lifecycle. To recover valuable recyclates from the NIPU foam, chemical recycling was used by targeting the molecular design incorporating organic carbonates. The initial reaction of lignin with organic carbonates creates etherified and carboxylated chains extending from the lignin structure that can be used as molecular handles to unravel the polymeric structure. In addition, the urethane bond has been shown to be capable of depolymerization in alkaline conditions [3]. Alkaline hydrolysis proved to be an efficient method of depolymerization allowing for the recovery of lignin and diamine through precipitation and solvent extraction. Most importantly, the researchers have been able to show that the original hydroxyl content of lignin is partially restored during chemical recycling, an important step in confirming that the recycled precursors have similar properties to virgin materials. Indeed, the biggest hurdles in using chemical recycling are the side reactions associated with lignin’s own reactivity described earlier. To mitigate against the tendency of lignin to condensate into insoluble material of lower value, additives can be used during chemical recycling that protect the lignin structure and render it more valuable in its recycled form. Using this unique recycling process, it was possible to resynthesize the NIPU with 100 % recycled content. The study aimed at synthesizing 100 % biobased, non-toxic, and recyclable PUs has taught the scientists many lessons. The first is an old one: when given lemons, make lemonade! Instead of seeing lignin’s own reactivity as a roadblock, why not harness its reactive nature to produce reactive precursors? Finding a path to lignin functionalization was the key to producing PUs that can compete with commercial materials. Secondly, when designing a circular lifecycle look towards nature’s own path for degradation. The rich amount of carbon-oxygen bonds inserted during lignin functionalization mimic the natural decomposition pathways of typical biomass. While an enzymatic route was not taken in this approach (typical of composting mechanisms) it was still possible to use a benign hydrolysis technique to revert waste foams back to usable precursors. These innovative techniques do not have to be reserved only for PUs. The goal and philosophy of the Clemson team is to incorporate this design for recyclability and non-toxicity into other types of polymers to enable a circular lifecycle for some of the most highly used commodity plastics. References: [1] Geyer, R.; Jambeck, J. R.; Law, K. L. Production, Use, and Fate of All Plastics Ever Made. Sci. Adv. 2017, 3 (7). [2] Lithner, D.; Larsson, Å.; Dave, G. Environmental and Health Hazard Ranking and Assessment of Plastic Polymers Based on Chemical Composition. Sci. Total Environ. 2011, 409 (18), 3309–3324. [3] Simón, D.; Borreguero, A. M.; de Lucas, A.; Rodríguez, J. F. Recycling of Polyurethanes from Laboratory to Industry, a Journey towards the Sustainability. Waste Manag. 2018, 76, 147–171. [4] Sternberg, J.; Sequerth, O.; Pilla, S. Green Chemistry Design in Polymers Derived from Lignin: Review and Perspective. Progress in Polymer Science. Elsevier Ltd February 1, 2021, p 101344. [5] Sternberg, J.; Pilla, S. Materials for the Biorefinery: High Bio-Content, Shape Memory Kraft Lignin-Derived Non-Isocyanate Polyurethane Foams Using a Non-Toxic Protocol. Green Chem. 2020. [6] Pilla, Srikanth; Sternberg, J. Non-Isocyanate Polyurethanes from Biobased Polyols. 63/034,584, 2020. [7] Schutyser, W.; Renders, T.; Van den Bosch, S.; Koelewijn, S.-F.; Beckham, G. T.; Sels, B. F. Chemicals from Lignin: An Interplay of Lignocellulose Fractionation, Depolymerisation, and Upgrading. Chem. Soc. Rev. 2018, 47 (3), 852–908. [8] Zhang, K.; Nelson, A. M.; Talley, S. J.; Chen, M.; Margaretta, E.; Hudson, A. G.; Moore, R. B.; Long, T. E. Non-Isocyanate Poly(Amide- Hydroxyurethane)s from Sustainable Resources. Green Chem. 2016, 18 (17), 4667–4681. www.clemson.edu High Pressure Hydrolysis Precipitation / washing Waste NIPU Foram Solubilized Foam Lignin Recovery 16 bioplastics MAGAZINE [01/21] Vol. 16
VIVALDI A change of tune for the chemical industry: The European Union has awarded EUR 7 million to the VIVALDI project to transform the biobased industry into a new, more environmentally friendly and competitive sector. To reach climate targets, industries need to accelerate the transition towards a low-carbon, resource-efficient, and circular economy. The chemical sector is one of the most challenging, but also a very promising one, in that context. At the forefront of waste reutilization, biobased industries (BIs) have the potential to lead the way and create a new and more sustainable sector based on the principle of carbon capture and utilization (CCU) also called CO 2 recycling. Based on this circular concept, BIs’ will reduce their greenhouse gas (GHG) emissions, their dependency on fossil carbon import and the exploitation of key resources such as energy, raw materials, land, and water. Starting in June 2021, the EU Horizon 2020 project VIVALDI (innoVative bIo-based chains for CO 2 VALorisation as aDdedvalue organIc acids) will develop a set of breakthrough biotechnologies to transform real off-gases from key BI sectors (Food & Drinks, Pulp & Paper, Bioethanol, and Biochemicals) into novel feedstock for the chemical industry. The core of VIVALDI solution is to capture, enrich, and transform in a two-step process (electrochemical and biological) the CO 2 captured into four platform organic acids. These resulting compounds have various applications: they can be used in the same site, enhancing the sustainability and circularity of BIs processes and products, or open new business opportunities as building blocks for novel biomaterial (e.g. bioplastics and animal feed). By integrating this concept, industries will “kill two birds with one stone”: not only BIs’ carbon emissions will be reduced, but the production of organic compounds that today is very energy-intensive will become cheaper and more sustainable. Replicability will be a key aspect of VIVALDI solutions, allowing other biorefineries and other industrial sectors to become more circular and reduce their environmental impact. The success of the project will be ensured by a multidisciplinary and international consortium led by the GENOCOV research group of Universitat Autònoma de Barcelona (Spain). The 16 partners range from BIs (SunPine, Damm, and Bioagra) and technology developers (VITO, UFZ, LEITAT, Processium, Avantium, Universitat Autònoma de Barcelona, University of Natural Resources and Life Sciences (Vienna), Luleå University of Technology) to enduser (Nutrition Sciences). Novamont will research how to use CO 2 along its entire value chain: from the capture of its CO 2 emissions to the conversion of it into new biochemicals. The team is complemented by three knowledge hubs: the sustainability and circularity expert group (BETA from Universitat de Vic, Barcelona, Spain), the technology and innovation consultancy (ISLE Utilities – London, UK), and the European Association representing the Carbon Capture and Utilisation community in Europe (CO 2 Value Europe, Brussels, Belgium). The consortium is ready to transform biorefineries, envisioning a new CO 2 -based industrial sector that contributes to largely decreasing the carbon footprint of the industry and boosting the EU’s economy. The VIVALDI project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 101000441. AT https://cordis.europa.eu/project/id/101000441 From Science & Research Drivers for regulation changes CO 2 Negative GHG emissions Purification & conversion Formic Acid Ground-breaking technologies Policy makers 3-Hydroxypropionic Acid (3-HP) Nutrient Recovery Methanol Ammonium, salts Bioproduction of organicacids Industrial validation Lactic Acid (LA) Succinic Acid (SA) Society Raise awareness Less pollutedwastewater New business models More sustainable products New biopolymers Easy replicability Itaconic Acid (IA) bioplastics MAGAZINE [01/21] Vol. 16 17
